This invention relates to an optimized high pressure internal combustion engine that intergrates certain features of our opposed piston engine with dual connecting rods and crank shafts as disclosed in our U.S. Pat. No. 4,791,787 entitled, REGENERATIVE THERMAL ENGINE issued on Dec. 20, 1988 and in our U.S. Pat. No. 4,809,646 entitled, HIGH PRESSURE RECIPROCATOR COMPONENTS, issued Mar. 7, 1989. The improvements herein described relate both to improved engine components and to improved engine operation.
In designing a high pressure, high r.p.m. engine that has auto ignition of the fuel, the configuration of the combustion chamber and the process of injection of the fuel become critical factors in achieving full combustion of the injected fuel without excessively high temperature zones that generate undesirable nitrogen oxides or without uniform flame fronts that can cause engine knock and piston damage. In a highly supercharged engine combustion pressures and temperatures can reach a level that produces deformations and asymmetries in the piston head that cause excessive friction or require excessive tolerances that inhibit efficient sealing. Furthermore, extremely high pressures in a reciprocal engine result in oil film breakdown in conventional wrist pin assemblies that connect the piston to a conventional piston rod and crank shaft assembly. At a high level of supercharging associated with a high r.p.m. engine, the time within which to efficiently burn the fuels for maximized development of power is extremely short. Inefficient combustion results in fuel waste and power loss as well as increases in noxious emissions. All of these problems have inhibited development of efficient high temperature and pressure reciprocal engines that have short piston strokes and that operate at high r.p.m.
Several of the above mentioned problems in engine design have been solved by applicants in their prior patents entitled REGENERATIVE THERMAL ENGINE and HIGH PRESSURE RECIPROCATOR COMPONENTS referenced above. In addition, applicants have devised symmetrical piston configurations as described in U.S. Pat. No. 4,858,566, issued Aug. 22, 1989, entitled, AXIALLY SYMMETRICAL PISTON FOR RECIPROCAL ENGINES. The engine herein described utilizes certain of the techniques and features disclosed in these prior references and includes new features and improves both the components used and the manner of operating the engine, particularly a single cylinder, opposed piston engine.
In particular, applicants have devised a phase cycling of the opposed pistons in the single cylinder engine such that the effective cycle duration of the maximum compression period is prolonged to enable and insure complete mixing and combustion of the injected fuel. Furthermore, the combustion chamber includes a central, specially configured regional chamber for initial combustion that is designed to cooperate with the phased cycling of the pistons for maximizing the turbulence of the compressed air and injected fuel by a double, sequential squish action.
In addition, the piston construction has been designed to maximize both the dual wrist pin assembly and axially symmetrical piston head assembly by a unique combination of such assemblies to enable the piston to structurally and dynamically withstand the inordinately high pressures developed during the improved combustion process. To achieve these super-high combustion pressures, the engine is charged by a unique counterrotating turboblower that is connectable in one stage to the engine drive train and in a second stage to an exhaust turbine. The turboblower is designed to produce compressed air both at low idle speeds where the expanding exhaust gases are insufficient to drive a turbocompressor and at high engine speeds where the exhaust expansion provides for total drive of both compression stages for peak compression in the turboblower. Although the various components in the preferred engine design disclosed herein have independent merit, the preferred use of these features and components is in the improved engine assembly disclosed herein.